U.S. patent application number 16/127388 was filed with the patent office on 2019-03-14 for structured packing element having a spiral helix shape.
This patent application is currently assigned to AXENS. The applicant listed for this patent is AXENS. Invention is credited to Driss AIT-MHAND, Florence BERNARD, Marie-Amelie LAMBERT, Jean-Philippe TOUPANCE.
Application Number | 20190076815 16/127388 |
Document ID | / |
Family ID | 60515565 |
Filed Date | 2019-03-14 |
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United States Patent
Application |
20190076815 |
Kind Code |
A1 |
LAMBERT; Marie-Amelie ; et
al. |
March 14, 2019 |
STRUCTURED PACKING ELEMENT HAVING A SPIRAL HELIX SHAPE
Abstract
The present invention also relates to a packing structure
obtained by assembling packing elements having a spiral helix
shape. The present invention also relates to the use of a
structured packing composed of packing structure for an operation
for bringing a gas into contact with a catalyst, and a process for
manufacturing such a structured packing.
Inventors: |
LAMBERT; Marie-Amelie;
(Chatou, FR) ; AIT-MHAND; Driss; (Bondy, FR)
; BERNARD; Florence; (Clichy, FR) ; TOUPANCE;
Jean-Philippe; (Paris, FR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
AXENS |
Rueil Malmaison Cedex |
|
FR |
|
|
Assignee: |
AXENS
Rueil Malmaison Cedex
FR
|
Family ID: |
60515565 |
Appl. No.: |
16/127388 |
Filed: |
September 11, 2018 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B01J 19/32 20130101;
B01J 2219/32213 20130101; B01J 2219/32408 20130101; B01J 2219/315
20130101; C10G 11/182 20130101; B01J 8/34 20130101; B01J 2219/3282
20130101; B01J 2219/32258 20130101; B01J 2219/32203 20130101; B01J
2219/30265 20130101; B01J 2219/32268 20130101; B01J 2219/3306
20130101; B01J 2219/30475 20130101 |
International
Class: |
B01J 19/32 20060101
B01J019/32; B01J 8/34 20060101 B01J008/34; C10G 11/18 20060101
C10G011/18 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 12, 2017 |
FR |
1758444 |
Claims
1) Packing structure (20) composed of at least two juxtaposed
series of identical packing elements (21), in which said packing
elements (21) are twisted plates having a spiral helix shape, a
series comprises at least two packing elements (21) adjoining in
the direction of their heights, and the packing elements (21) of
two separate series are juxtaposed in a substantially parallel
fashion and in the direction of their heights.
2) Packing structure (20) according to claim 1 comprising n series
of packing elements (21), said series comprising m adjoining
packing elements, Where n is comprised between 1 and 300 and m is
comprised between 2 and 300.
3) Packing structure (20) according to claim 1 characterized in
that the edges (22, 23) of the two ends of each of the packing
elements are substantially parallel to each other.
4) Packing structure (20) according to claim 1 characterized in
that the edges (22, 23) of the two ends of the packing elements
(21) of one and the same series are substantially parallel to each
other.
5) Packing structure (20) according to claim 4 characterized in
that the packing structure comprises at least two series in which
the edges (22, 23) of the ends of the packing elements (21) of two
juxtaposed series are substantially perpendicular.
6) Packing structure (20) according to claim 1 characterized in
that the pitch (p) of the spiral helix of a packing element (21) is
comprised between 10 and 30 cm.
7) Packing structure (20) according to claim 1 characterized in
that the pitch (p) of all the packing elements is identical.
8) Packing structure (20) according to claim 1 characterized in
that the width (1) of each of the packing elements is comprised
between 5 and 30 cm.
9) Packing structure (20) according to claim 1 characterized in
that the height (h) of the packing structure (21) is comprised
between 20 and 100 cm.
10) Packing structure (20) according to claim 1 characterized in
that the height (h) of the packing structure is equal to at least
twice the pitch (p) of the spiral helix of the packing elements
(21) having the highest value of pitch (p).
11) Structured packing (15) composed of at least two packing
structures (20) according to claim 1.
12) (canceled)
13) A process for stripping a catalyst, comprising stripping said
catalyst with a gas in the presence of a structured packing (15)
according to claim 1.
Description
[0001] The present invention relates to the field of structured
packing, used in particular for an operation of stripping
hydrocarbons entrained or adsorbed on catalyst particles.
[0002] The invention can in particular relate to the field of
cracking processes. The present invention can in particular be
implemented in a fluid catalytic cracking (FCC) process for
cracking heavy feedstocks such as vacuum residues or vacuum
distillates, but also in FCCs treating lighter feedstocks. It can
also be implemented in naphtha catalytic cracking (NCC) units or
also deep catalytic cracking (DCC) or high severity fluid catalytic
cracking (HS-FCC) units, or also in methanol to olefins (MTO) or in
methanol to gasoline ((MTG) conversion units.
[0003] More particularly, the present invention can be used in
fluid catalytic cracking units, also called FCC units in the
remainder of this description.
[0004] The FCC units can operate either with a single riser reactor
or downflow reactor geared towards the production of gasoline, or
with two reactors, a main reactor geared towards the production of
gasoline and a secondary reactor geared towards the production of
propylene.
[0005] In an FCC process, the hydrocarbons are brought into contact
in the reactor with a finely divided catalyst. During the cracking
reaction, hydrocarbons, some of which are partially cracked, are
deposited on the catalyst. These more-or-less cracked hydrocarbons
are generally called "coke". It is therefore necessary to transport
the catalyst to one or more regenerators in order to continuously
remove these hydrocarbons and thus regenerate the catalyst.
[0006] However, it is necessary, before sending spent catalyst to
the regenerator, to remove beforehand all or part of the
hydrocarbons which have penetrated the high porosity of the
catalyst or which are adsorbed on its surface. This makes it
possible to reduce and better control the temperature at the
regenerator, and to improve the recovery of upgradable products
originating from cracking. This operation is carried out in a
stripper in which a gas, generally steam, is circulated in
counter-current to the flow of catalyst. Said gas becomes loaded
with gaseous hydrocarbons thus removed from the surface or from the
porosity of the catalyst. The efficiency of this operation is
increased by the addition of baffles or packing in the stripping
zone.
[0007] The baffles or packing are generally arranged in the lower
part of the stripper in the dense phase so as to reduce
entrainments of solid particles towards the dilute phase.
[0008] Efficient stripping of the hydrocarbons and coke precursors
present on the spent catalyst is essential, insofar as the
feedstocks treated are increasingly heavy, which requires more
severe cracking operating conditions and leads to the formation of
more significant quantities of coke on the catalyst.
[0009] In a fluidized-bed catalytic unit, the packing arranged in
the stripping zone has the advantage of ensuring a good
distribution of the catalyst in the stripping zone and having a
good efficiency of contact between the spent catalyst and the
stripping fluid.
[0010] Moreover, the structured packing is also used for bringing
fluids into contact, in particular in the fields of gas treatment,
distillation, acid gas capture, dehydration or air separation. For
these fields of use, the packing fulfils similar functions to the
packing used for the stripping. For these uses, the packing also
has to be simple and quick to assemble within the column.
[0011] The present invention relates to an element of structured
packing having a spiral helix shape.
[0012] The present invention also relates to a packing structure
obtained by assembling such packing elements, the use of such a
packing for an operation of bringing a gas and a catalyst into
contact, and a process for manufacturing such a structured
packing.
[0013] The packing structure according to the present invention
makes it possible to obtain a better and homogeneous radial
distribution of the solids and/or of the fluids brought into
contact, in particular of the particles of catalyst along the
spiral helixes, and thus improves the contact between the particles
of catalyst and the vapour phase for the case of stripping.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] Other characteristics and advantages of the device and
process according to the invention will become apparent on reading
the following description of non-limitative embodiment examples,
with reference to the attached figures which are described
below.
[0015] FIG. 1 shows a stripper according to an embodiment of the
invention. FIG. 1a is a general view of a stripper including a
packing structure according to the invention. FIG. 1b shows the
structured packing of the stripper of FIG. 1.
[0016] FIG. 2 represents a packing element according to an
embodiment of the invention.
[0017] FIG. 3 represents a plan view of one end of a packing
structure according to an embodiment of the invention.
[0018] FIG. 4 represents a three-dimensional view of a packing
structure according to an embodiment of the invention.
[0019] FIG. 5 shows a three-dimensional view of a set of two
packing structures according to an embodiment of the invention.
DETAILED DESCRIPTION OF THE INVENTION
[0020] Packing Structure
[0021] The present invention relates to a structured packing
structure. By "structured packing" is meant a juxtaposition of
several unit elements, also called packing elements, identical or
not, arranged in an ordered manner. According to the invention, the
unit element of structured packing is a twisted plate substantially
having a spiral helix shape. The dimensions of the plate are chosen
so that they make it possible to obtain a spiral helix by twisting
said plate.
[0022] According to the invention, the packing structure is
composed of a number n of vertical series of juxtaposed packing
elements, where n is at least equal to 2. Each series is composed
of m packing elements adjoining in the direction of their height,
where m is at least equal to 2. The packing elements of two
separate vertical series are juxtaposed in a substantially parallel
fashion in the direction of their height. Seen from above, within a
series, the packing elements are aligned.
[0023] The packing structure according to the present invention
makes it possible to obtain an optimized and homogeneous radial
distribution of the solids and/or of the fluids brought into
contact along the spiral helixes, which makes it possible to
improve the exchanges between the solids and/or the fluids. In
particular, the packing structure according to the invention makes
it possible to obtain a homogeneous radial distribution of the
particles of catalyst along the spiral helixes, and thus improves
the contact between the particles of catalyst and the vapour phase
for the case of stripping.
[0024] Preferably, the packing structure comprises n vertical
series of packing elements, said series independently comprise a
number m of adjoining packing elements, in which, [0025] n is
comprised between 1 and 300, preferably between 2 and 300, and more
preferably between 10 and 250, and [0026] m is comprised between 2
and 300, preferably between 15 and 200.
[0027] According to an aspect of the invention, the packing
structure can have a height comprised between 20 and 50 cm,
preferably between 20 and 40 cm. This dimension allows an insertion
of the packing structure into the column. In addition, this
dimension substantially corresponds to the length of a packing
element.
[0028] In order to reinforce the stability and the strength of the
packing structure, a positive connection of the structure is
implemented by fixing the packing elements, for example by welding,
by bonding, by screwing, by bolting, or any similar means.
Preferably, the fixing is implemented by welding.
[0029] Packing Element
[0030] According to the invention, the packing element comprises,
preferably is constituted by, a twisted plate having a spiral helix
shape. Preferably, the twisted plate before twisting is
substantially rectangular. Said packing element is characterized in
particular by its height, its width, the value of pitch defining
the twist, and the thickness of the twisted plate.
[0031] Preferably, the thickness, denoted e, of the plate of the
packing element is comprised between 2 and 10 mm, preferably
between 4 and 8 mm. This thickness allows twisting of the plate
into a spiral helix by any means known to a person skilled in the
art.
[0032] Preferably, the height, denoted h, of the packing element is
comprised between 20 and 100 cm, preferably between 22 and 80 cm
and preferably between 25 and 50 cm. This height allows an
insertion into a column (for example a stripper).
[0033] Preferably the width, denoted I, of the packing element is
comprised between 5 and 30 cm and preferably 8 and 25. Thus, the
spaces formed in the structured packing have dimensions suitable
for promoting the exchanges between the two fluids or between a
fluid and solids (for example catalyst).
[0034] Preferably, the pitch of the packing element, denoted p,
characterizing the helix is comprised between 10 and 30 cm, and
preferably between 10 and 20 cm. By "pitch" is meant the distance
separating two adjacent crests of the spiral helix parallel to the
height of said helix.
[0035] Preferably, the pitch of all of the packing elements of one
and the same series is identical. Preferably, the pitch of all of
the packing elements comprising a packing structure is identical,
and thus advantageously allows a regular structure to be
obtained.
[0036] Preferably, the two edges of the two ends of a packing
element are parallel. By "edge" (22 and 23) is meant the ends of
the packing element the dimension of which corresponds to the width
of the plate. Thus, the packing element forms a whole number of
helixes.
[0037] Preferably, the extreme edges of the packing elements of one
and the same vertical series are parallel to each other.
[0038] Preferably, the edges of the two ends of a packing element
are perpendicular to the height of said packing element.
[0039] Preferably, when the edges of the packing elements of a
first vertical series are parallel to each other, the edges of the
packing elements of the juxtaposed second vertical series are
perpendicular to the edges of the first series. Thus, the packing
structure can comprise packing elements with a plurality of series
of packing elements with series for which the extreme edges are
orientated in a first direction, and with series for which the
extreme edges are orientated in a second direction perpendicular to
the first direction. For this embodiment, the series in the second
direction are juxtaposed between the series in the first
direction.
[0040] Preferably, the edges of four adjacent packing elements of
two juxtaposed series form a square the edges of which are
constituted by the edges of said four elements.
[0041] Preferably, the height (h) of the packing structure (20) is
equal to at least twice the pitch (p) of the spiral helix of the
packing element (21) having the highest value of pitch (p). Thus,
the packing elements comprise at least two twists.
[0042] According to an embodiment, the packing element can be made
of metal. It can be formed by machining, by moulding, by plastic
deformation of a flat plate or by additive manufacturing.
[0043] The packing elements are assembled according to the
invention in a packing structure by any means known to a person
skilled in the art.
[0044] Another subject of the invention relates to a structured
packing comprising, preferably constituted by, packing structures
according to the invention.
[0045] According to a preferred embodiment, the structured packing
is composed of a plurality of packing structures independently
comprising a number n of series, each of the series independently
comprising a number m of packing elements in which n and m can take
the values as defined previously.
[0046] Advantageously, the structured packing has a circular shape
suitable for its use in a catalyst stripping operation.
[0047] FIG. 2 shows, diagrammatically and non-limitatively, a
packing element according to an embodiment of the invention. The
packing element 21 has a spiral helix shape, with a height denoted
h, a width denoted I, a pitch denoted p, a lower edge 22 and an
upper edge 23 (the thickness, which is not shown, is less than the
height h and the width I).
[0048] FIGS. 3, 4 and 5 represent, diagrammatically and
non-limitatively, a packing structure according to an embodiment of
the invention.
[0049] FIG. 3 is a view of the lower end of a packing structure 20.
Said structure comprises 4 series (denoted n), each of the series
comprising 2 packing elements (21) (denoted m). The edges (22) of
the packing elements (21) of one and the same series are parallel,
and the edges of the packing elements of two adjoining series are
perpendicular.
[0050] FIG. 4 is a three-dimensional view of the packing structure
20. The packing structure comprises 4 series (denoted n), each of
the series comprising 2 packing elements (21) (denoted note m). The
lower edges (22) of the packing elements (21) of one and the same
series are parallel, and the lower edges (22) of the packing
elements of two juxtaposed series are perpendicular. The upper
edges (23) are arranged in an identical fashion to the lower edges
(22).
[0051] FIG. 5 is a three-dimensional view of a packing composed of
2 packing structures, each of the structures comprising 4 series
(denoted n), each of the series comprising 2 packing elements (21)
(denoted m). The lower edges (22) of the packing elements (21) of
one and the same series are parallel, and the lower edges (22) of
the packing elements of two juxtaposed series are perpendicular.
The upper edges (23) are arranged in an identical fashion to the
lower edges (22).
[0052] Uses
[0053] Moreover, the present invention relates to a use of a
packing structure according to any combination of the
characteristics described previously for bringing a gas into
contact with a catalyst, in particular for a stripping operation of
a catalyst, for example for an FCC, NCC, DCC, HS-FCC, MTO, MTG
process or any similar process.
[0054] During this stripping operation of the catalyst, all or part
of the hydrocarbons which have penetrated the high porosity of the
catalyst or which are adsorbed on its surface are removed. That
makes it possible to reduce and better control the temperature at
the regenerator (operation after stripping), and to improve the
recovery of upgradable products originating from cracking. This
operation is carried out in a stripper in which a gas, generally
steam, is circulated in counter-current to the flow of catalyst.
Said gas becomes loaded with gaseous hydrocarbons thus removed from
the surface or the porosity of the catalyst. The efficiency of this
operation is increased by the addition of packing in the stripping
zone.
[0055] The packing is arranged in the lower part of the stripper in
the dense phase so as to reduce the entrainments of solid particles
towards the dilute phase.
[0056] In a fluidized-bed catalytic unit, the packing according to
the invention has the advantage of ensuring a good distribution of
the catalyst in the stripping zone and of having a good efficiency
of contact between the spent catalyst and the stripping fluid.
[0057] For this use, the stripping chamber can comprise: [0058] a
system for the separation of the catalyst and the cracked gases,
[0059] a cyclone for separating a fraction of catalyst, [0060] a
packing as described previously for bringing the catalyst into
contact with a gas with the aim of removing the hydrocarbons that
have penetrated or been adsorbed by the catalyst, and [0061] at
least one gas insertion pipe for distributing the gas over the
packing.
[0062] FIG. 1 a shows, diagrammatically and non-imitatively, a
general view of a stripper S including a packing structure
according to an embodiment of the invention. This figure shows the
top part of the riser reactor 1 which opens into a separation
system 2 making it possible to separate the catalyst and the
cracked gases. Said system can be of any type known to a person
skilled in the art. The cracked gases are sent via the pipe 3 into
the cyclone 6 and leave the disengaging vessel 4, situated above
the stripping zone of the stripper S, via the pipes 5 and 17.
[0063] An additional fraction of catalyst is separated in the
cyclone 6 and sent into the dipleg 7 in order to arrive in the
dense catalyst bed 8 situated a little lower, above the packing 15.
The packing 15 is obtained by superimposition of several structured
packing layers as described previously. The packing 15 is held in
the stripper S via grids or supports 16. The catalyst is stripped
by the steam admitted via the ducts 9a, 9b and 9c then sent to the
regenerator (not shown) via the pipe 11. The optional element 12
allows an injection of steam at the top of the stripper in order to
discourage the formation of coke. The element 13 is a guide making
it possible to keep the separation system 2 away from the wall of
the disengaging vessel 4.
[0064] FIG. 1b shows, diagrammatically and non-imitatively, a more
detailed view of the packing 15 of FIG. 1a.
[0065] Generally a structured packing is obtained by
superimposition and/or juxtaposition of several layers of packing
structure, preferably 2 to 20 layers of packing structure, more
preferably 3 to 15 layers and very preferably 4 to 10 layers.
[0066] The structured packing according to the invention is also
used for bringing fluids, for example a gas and a liquid, into
contact, in particular in the fields of gas treatment,
distillation, acid gas capture, dehydration or air separation.
[0067] Manufacturing Process
[0068] The present invention also relates to a manufacturing
process of a packing structure, in which the following steps are
carried out: [0069] a) manufacturing a plurality of packing
elements according to any one of the combinations of
characteristics previously described, for example by machining, by
moulding, by plastic deformation of a flat plate or by additive
manufacturing; [0070] b) constructing an arrangement of the packing
elements by means of the following steps: [0071] i) positioning at
least two packing elements of a first series of packing elements in
one direction; [0072] ii) assembling at least two packing elements
of a second series of packing elements in the direction of the
height of the elements of the first series; [0073] iii) repeating
steps i) and ii) in order to form the desired volume.
[0074] Thus assembled, the packing elements of the two series form
a three-dimensional mesh delimiting channels for promoting the
exchanges. The spiral helixes of the packing elements allow a
better radial distribution of the elements to be brought into
contact (in particular for a gas with particles of spent
catalyst).
[0075] Preferably, the manufacturing process comprises a step of
fixing the packing elements together, in particular by welding,
bonding, screwing, bolting or any similar means. Preferably, the
positive connection is implemented by welding.
[0076] According to an implementation of the invention, the
manufacturing process comprises a step of cutting the packing
structure to the desired shape, in particular according to an
angular portion of a cylinder (i.e. substantially the shape of a
portion of camembert). Thus, the insertion of the packing into a
column is facilitated, as well as its assembly
[0077] Preferably, the extreme edges of the packing elements of the
first series are substantially perpendicular to the extreme edges
of the packing elements of the second series.
[0078] Without further elaboration, it is believed that one skilled
in the art can, using the preceding description, utilize the
present invention to its fullest extent. The preceding preferred
specific embodiments are, therefore, to be construed as merely
illustrative, and not limitative of the remainder of the disclosure
in any way whatsoever.
[0079] The entire disclosures of all applications, patents and
publications, cited herein and of corresponding application No. FR
1758444, filed Sep. 12, 2017 are incorporated by reference
herein.
[0080] From the foregoing description, one skilled in the art can
easily ascertain the essential characteristics of this invention
and, without departing from the spirit and scope thereof, can make
various changes and modifications of the invention to adapt it to
various usages and conditions.
* * * * *